The Western Area Power Administration’s Desert Southwest Region (DSW) signed an implementation agreement Wednesday to join CAISO’s Western Energy Imbalance Market (WEIM), making it the second WAPA region to seek entry to the market in recent years.
DSW has been working with its customers for two years to “determine the most beneficial course of action for us and for our customers,” WAPA Administrator Tracey LeBeau said in a joint statement with CAISO on Thursday.
“Joining the EIM will support DSW’s ability to economically market and dispatch energy on a timely basis and meet the needs of our customers,” LeBeau said. “We look forward to working with the ISO and our partner utilities to implement the EIM in our balancing authority and take advantage of the many resources and flexibilities the EIM offers.”
WAPA’s Sierra Nevada Region, part of the Balancing Area of Northern California, became an active WEIM participant in April. (See Expansion Takes EIM into LA, New Mexico.) Parts of WAPA’s Upper Great Plains West and Rocky Mountain regions decided to join SPP’s competing Western Energy Imbalance Service (WEIS), which launched in February. (See WAPA, Basin, Tri-State Sign up with SPP EIS.)
The implementation agreement also applies to WAPA’s Western Area Lower Colorado Balancing Authority, which includes generating resources in the Boulder Canyon and Parker-Davis projects (PDP) and the transmission systems of the PDP, Central Arizona Project and the Pacific-Northwest-Pacific Southwest Intertie Project.
DSW sells federal hydroelectric power and provides transmission service to dozens of cities, electric cooperatives, Native American tribes, government agencies and irrigation districts. One of its customers, the Arizona Electric Power Cooperative (AEPCO), includes six distribution cooperatives and five public power entities that serve more than 420,000 residential, agriculture and corporate customers.
“Joining the Western EIM will ensure AEPCO and its members have real-time access to a much larger regional energy market,” Jon Martell, AEPCO executive director of energy services, said in the joint statement.
Other participating BAs include the Central Arizona Water Conservation District, Southwest Public Power Agency and DSW customers in Arizona, Southern California and southern Nevada.
“We are very pleased to welcome the WAPA DSW region and the Arizona Electric Power Cooperative to the Western EIM,” CAISO President and CEO Elliot Mainzer said in the statement. “I appreciate the thoughtfulness that went into their decision and look forward to working together to create additional economic and environmental value for their constituents and the broader EIM community.”
The WEIM now has 15 active participants in 10 Western U.S. states and part of British Columbia. Eight more entities are set to join in 2022 and 2023, potentially encompassing 84% of electric demand in the Western Interconnection. By allowing low-cost energy to be bought and sold in real time across state lines, it has provided more than $1.4 billion in benefits to its members since launching in 2014, according to CAISO.
